Organic acidurias in Egyptian children: The urge for high-risk screening.

BACKGROUND: Organic acidurias are a group of inborn errors of metabolism. They present a significant diagnostic challenge and are associated with serious morbidity and mortality. They are considered the most frequent inborn errors of metabolism among high-risk children. Gas chromatography-mass spectrometry is a reliable diagnostic technique for organic acidurias. This hospital-based study aimed to quantify the frequency of organic acidurias among a group of high-risk Egyptian pediatric patients and to highlight the importance of high-risk screening for such disorders. METHODS: One hundred and fifty high-risk children who presented to the inherited metabolic disease unit and the pediatric intensive care units of Cairo University Children Hospital were tested for urine organic acids using gas chromatography-mass spectrometry. RESULTS: Thirty percent (45/150) of the patients were confirmed as having an altered organic acids profile. Neurological manifestations were the most common presentation. Glutaric aciduria type I and maple-syrup urine disease were the most common disorders encountered among the group that was studied. CONCLUSION: Organic acid detection by gas chromatography-mass spectrometry is key to the diagnosis of many metabolic disorders. Until a national expanded newborn screening program is established, high-risk screening is strongly encouraged for the early detection of, and proper intervention for such disorders among Egyptian children.

Creatine Deficiency Syndromes: Comparison of Screening Methods and Characterization of Four Novel Intronic Variants.

BACKGROUND: Cerebral creatine deficiency syndromes (CCDS) are disorders affecting creatine synthesis or transport. Several methods have been developed to measure creatine and guanidinoacetate (GAA) in different body fluids including methods based on gas chromatography-mass spectrometry (GC-MS) and High-pressure liquid chromatography mass spectrometry (HPLC-MS). The diagnosis of CCDS is then confirmed by sequencing of creatine biosynthesis genes guanidinoacetate methyltransferase (GAMT) and Arginine: glycine amidinotransferase (GATM) and creatine transporter gene solute carrier family 6 member 8 (SLC6A8) or by functional enzymatic assay. The aim of the current study was to find the most reliable and accurate screening method for CCDS by comparing methods using Nuclear Magnetic Resonance spectroscopy (NMR), GC-MS and HPLC-MS. Additionally, this study was performed to estimate the prevalence of CCDS in a cohort of Egyptian patients and potentially to discover novel variants. SUBJECTS AND METHODS: The study was conducted on 150 subjects with clinical signs and symptoms consistent with CCDS. Metabolic profiling of urine samples was performed using three techniques: 1) GC-MS 2) Ultra high-pressure (or performance) liquid chromatography - Tandem Mass Spectrometry (UHPLC- MS/MS) and 3) NMR. RESULTS: The linearity of peak areas for creatine and GAA by UHPLC-MS/MS and NMR covered and exceeded the ranges normally found in urine. The limit of quantification and the inter-day precision results for creatine and GAA were more robust by UHPLC-MS/MS than NMR. Ten cases were identified as being positive for CCDS by our analytical approaches and underwent next generation sequencing (NGS) for GAMT, GATM and SLC6A8 genes. NGS was performed and confirmed one patient with one likely Pathogenic variant in GAMT gene: (NC_000019.10:g.1401317C > G, NP_000147.1:p.Ala54Pro). Additionally, we describe four novel intronic variants in the GATM gene: c.1043-357del and c.1043-357_1043-356insT, and were predicted to activate cryptic acceptor site with potential alteration of splicing, c.979-227G > A was found to significantly alter the Exon Splice Enhancer (ESE) xon Splice Silencer (ESS) motifs ratio and c.1042 + 262del which was found to have no implications on splicing. CONCLUSIONS: Both UHPLC-MS/MS and NMR spectroscopy are comparable to GC-MS in screening for CCDS. Nonetheless, the UHPLC-MS/MS method had better performance than NMR spectroscopy. Additionally, Sequencing of the full length of GATM, GAMT, and SLC6A8 genes is needed to identify intronic variants that could cause CCDS via affecting splice sites.

Role of single nucleotide polymorphisms of the HSD3B1 gene (rs6203 and rs33937873) in the prediction of prostate cancer risk.

3­ß­hydroxysteroid dehydrogenase 1 (HSD3B1) is shown to affect dihydrotestosterone level in prostatic tissue which is a risk factor for prostate cancer (PC). The present study aimed to determine whether rs33937873 (G313A) and rs6203 (C338T) single nucleotide polymorphisms (SNP) in HSD3B1 gene was a potential risk factor for PC susceptibility and can predict the recurrence of PC in Egyptian patients. A total of 186 Egyptian patients were selected with incident primary PC and compared with 180 age healthy controls. The frequencies and the main effect of rs33937873 and rs6203 in HSD3B1 were compared and investigated between the patients and control using genotyping technique and statistical analysis. The mutant GA genotype of G313A in rs33937873 SNP was considered as an independent risk for PC in the multivariate regression analysis [odds ratio (OR)=2.7, 95% confidence intervals (CI): 1.2­5.5, P=0.01] together with positive history of hypertension (HTN) (OR=6.2, 95% CI: 3.2­12.1, P=0.0001) and begin prostatic hyperplasia (BPH; OR=8.9, 95% CI: 4.5­17.5, P=0.0001). Conversely, in rs6203 (C338T), C allele is considered as major risk allele in the development of PC (OR=1.8, 95% CI: 1.3­2.4, P=0.0003). The univariate logistic regression analyses indicated that CC genotype of rs6203 was a PC risk factor (OR=1.9, 95% CI: 1.3­2.9, P=0.002). In addition, the frequency of the A­C haplotype established by rs33937873­rs6203 was also significantly higher for PC (P=0.013). The predication of PC recurrence was associated only with positive family history (OR=7.7, 95% CI: 2.3­25.9, P=0.001) and not for The G313A and C338T SNPs. These results suggested that the two HSD3B1 polymorphisms rs33937873 and rs6203 may modify the risk of PC, particularly among patients with HTN and history of BPH, suggesting them as prominent future markers for prediction of PC risk.

Mitochondrial Complex I Deficiency among Egyptian Pediatric Patients with Steroid-Resistant Nephrotic Syndrome.

RESULTS: Positive consanguinity was a remarkable finding in 44 patients among the SRNS group (73%), compared with 33 patients among the SSNS group (55%). Complex I activity was significantly lower in the SRNS group (0.2657 ± 0.1831 nmol/ml/min), than in the SSNS group (0.4773 ± 0.1290 nmol/ml/min) (p < 0.001). There was a significant positive correlation between complex I activity and the heaviness of proteinuria among the SRNS group (r 0.344, p < 0.001). There were statistically significant differences in serum C3 and C4 levels between both groups (p < 0.001, 0.053, respectively). CONCLUSION: Mitochondrial complex I deficiency in patients who have a nephrotic syndrome complaint may play a role in their responsiveness to steroid therapy and the development of SRNS and even the prognosis of their illness.